1. Field of the Invention
The present invention relates to a laser machining apparatus for cutting and holing a workpiece by means of a laser beam.
2. Prior Art
FIG. 9 is a block diagram illustrating a conventional laser machining apparatus introduced in a publication (Catalog of Carbon Dioxide Gas Laser Machining Apparatus, Mitsubishi Denki Kabushiki Kaisha). In FIG. 9, numeral reference 1 denotes a workpiece secured to a table 2 as what is to be processed; 3, a machining head for irradiating the workpiece 1 with a laser beam 4 in a direction substantially perpendicular to the workpiece 1; 5, an X-axis drive mechanism for driving the table 2 in the horizontal X-axis direction; 6, a Y-axis drive mechanism for driving a Z-axis drive mechanism, which will be described later, in the horizontal Y-axis direction perpendicular to the horizontal X-axis direction; and 7, a Z-axis drive mechanism for driving the machining head 3 thus held in the Z-axis direction perpendicular to the surface of the workpiece 1, the Z-axis drive mechanism 7 being driven by the Y-axis drive mechanism 6 in the horizontal Y-axis direction.
FIG. 10 illustrates the movement of the workpiece 1 and the laser beam 4. In FIG. 10, there are shown mirrors 33 and 34 for turning the direction in which the laser beam 4 has been emitted from a laser oscillator (not shown).
The operation of the laser machining apparatus will subsequently be described. The workpiece 1 is set on the table 2 and moved by the horizontal X-axis drive mechanism in the X-axis direction as shown in FIG. 9. As shown in FIG. 10, moreover, the mirror 34 and the machining head 3 are moved by the Y-axis drive mechanism 6 to a desired position in the Y-axis direction, whereas the machining head 3 is moved by the vertical Z-axis drive mechanism 7 to a desired position in the Z-axis direction to vary the height. With the combination of these 3-axis drive mechanisms in operation, the relative position between the workpiece 1 and the machining head 3 is varied so that the workpiece 1 is processed by the laser beam irradiation 4 from the machining head 3.
As the conventional laser machining apparatus is thus constructed, the heavy table 2 and the like need moving even when machining is carried out in conformity with a microminiature configuration. When it is attempted to increase or decrease the machining speed sharply, the drive mechanism tends to run short of drive force or cause vibration, thus deteriorating machining precision. For this reason, machining is compelled to be carried out at low speed without increasing or decreasing the machining speed sharply in order to secure machining precision; the problem is that machining efficiency becomes extremely low.